Heat transfer device



Aug. 9, 1960 Filed April 1, 1957 J. R. MEHALICK EI'AL HEAT TRANSFERDEVICE 2 Sheets-Sheet 1 INVEN J. RIC RD ME CK. EDWA R. IZ

ATTORNEY.

Aug. 9, 1960 -R HALl cK EI'AL 2,948,515 I HEATPTRANSFER DEVICE FiledApril 1, 1957- 2 Sheets-Sheet 2 INVENTOR. J. RICHARD MEHALICK. BY EDWARDR. IZZO.

ATTORNEY.

' to flow over a coil in two different directions.

HEAT TRANSFER DEVICE John Richard Mehalick, Fayetteville, and Edward R.Izzo,

De Witt, N.Y., assignors to Carrier Corporation, Syracuse, N.Y., acorporation .of Delaware Filed Apr. 1, 1957, Ser. No. 650,042

1 Claim. (Cl. 257-137) This invention relates to heat transfer devices.More specifically this invention relates to a heat transfer deviceincluding tubular means having an extended surface construction such asa plurality of fins assembled thereabout.

Heat transfer devices or assemblies of the type described are widelyused in fields where a transfer of heat between a first medium flowingin the confined path within the tube or coil and a second medium flowingover the surface of the assembly is desired. This invention contemplatesa heat transfer device wherein the extended surface is in the form of aseries of spaced platesfa'ssembled. about the surface of the tube.Assemblies of this type are known generally as plate fin coils.'Under'some circumstances it is desirable that two separate paths of airflowing over the coil be provided. Likewise it is often desirable tocause one path ofTiali r 1s invention involves a plate fin coilconstruction wherein the plate fins are formed so that when assembledabout the coil, a barrier or partition is formed to define two separateand distinct portions of the coils so that either of the air flow pathsmentioned above may be obtained.

A chief object of this invention is the provision of a heat transferdevice of the type under consideration that may be employed undercircumstances where it is desired that there be two or more separatepaths across the face of the device for the flow of a medium such asair, or that there be flow paths for several media over the same heattransfer device.

Another object is the provision of an improved heat transfer devicewherein more efficient transfer of heat between a medium flowing withinthe device and a medium flowing over the surface of the device may beobtained.

Other objects and advantages of the invention will be apparent from aconsideration of the invention as described in the ensuingspecifications and drawings, in which Figure l is'a front view of a heattransfer coil forming the subject of this invention;

Figure 2 is a side view of one of the plate fins illustrated in Figure1;

Figure 3 is a front view of another of the fins illustrated in Figure 2;

Figure 4 is a side view of the fin illustrated in Figure 3;

Figure 5 is a front view of another of the fins illustrated in Figure 1;and

Figure 6 is a partial perspective view of an air conditioning unit ofthe room cooler type having assembled therein a heat transfer coilforming the subject of this invention.

In utilizing heat transfer coils of the kind described in airconditioning units of the room cooler type it is often desirable thatthe flow of air to be conditioned by the unit enters through the lowerportion of the heat transfer coil functioning as the evaporator, and isdischarged through the upper portion of the coil. In the 2 interest ofobtaining eificient operation of the unit, it is necessary that the-twoair streams described above be segregated by a wall or partition member.Heretofore it has been proposed that the coil be provided with aseparate member serving as the wall. This entails cutting the plate finsintermediate their ends.

' This invention contemplates a heat transfer coil of the type describedwherein the extended surface normally associated with such coil isformed so that portions thereof cooperate to provide the wall or barriermember for separating two parts or portions of the air stream.

Referring to Figure 1 it will be noted that there is disclosed a heattransfer device or coil 10 of a conventional type 'includinghorizontalsections of tubing 11, having a plurality ofreturn bends 11a connectingthem to form a continuous tubular member, having an inlet end 12, and anoutlet end 13, arranged to form a serpentine configurations In arefrigeration system of the type employed in conventional-room coolers,refrigerant in one phase is supplied to the device 10 through the inlet12 of the tubular construction. 1 The refrigerant changes phase in thedevice as air at a; temperature different from the temperature of therefrigerant flows over the member and flows therefrom through outlet 13.

Assembled about the outer surface of the device 10 is a series ofsubstantially rectangular shaped plates or fins having a relativelysmall dimension inadirection longitudinal-of thetube. :In theillustrated: embodiment ofthe inventiondhese plates are indicatedat 14.and 15. Openings 16 are provided in the plates to'accom modatesuccessive runs of the tubing 11. To complete the coil assembly, tubesheets 19 and 20 are provided at the opposed sides of the device asshown in Figure 1. In accordance with one feature of this invention theplates or fins 14 are provided with a protuberance 17 formed byupsetting a portion of the fin from its plane. The protuberance 17extends substantially transversely of the fin as indicated in Figure 2,extending from a first notch 60 in one edge of the plate to a secondnotch 61 in the opposed edge. The plates 15 are likewise provided with aprotuberance 18 of the type described above in conjunction with thedescription of fin 14 as well as with notches 60 and 61. It will benoted, however, that the protuberance 18 extends a slightly greaterdistance from the top edge of the plate 15 than the pro-v ly introducedover the surface of the coil or tube 11 so that an arrangement of thetype shown in Figure 1 is obtained. Under these circumstances it will beobserved that the protuberances 17 and 18 are each vertically offsetfrom the next adjacent protuberance to form a barrier or wall sufficientto maintain segregation of an air stream flowing over the top of theassembly in a manner to be later described.

Figure 5 illustrates an air conditioning unit of the room cooler typeequipped with a heat transfer device forming the subject of thisinvention. A casing 26 includes opposite side walls 27 and 28 connectedby a bottom wall 29. A cover 30 and a central partition 31 define, inconjunction with the casing, a chamber having an open end which may beeither the conventional high side or low side compartment of the unit.In addition to the structure described there is included an intermediateor horizontally disposed wall 34 having an opening 35 accommodating afan 36 driven by a motor, not shown. Across the front or open end of thechamber is disposed the coil or heat transfer device 10. An outer facade50 is arranged over the outer face of the coil and is prolatented Aug.9, 1960 vided with openings .51 having louvers 52 assembled therein. Theinner surface of the facade so has a ledge or shelf 53 adapted to engagein the recess formed by the individual notches 60 in one edge of thefin. The wall 34 is arranged to engage with the recess formed by notches61 in the opposed edge of the, fins. The parts are so arranged that thebarrier formed by the protuberances 17 and 18 cooperates with the wall34- and ledge 53 to define a path for a first portion of an air streammoving into the chamber under the influence of the fan 36 across thelower portion of the coil, and a path for a second portion of an airstream being discharged from the chamber over the upper or top portionof the coil.

Thus it will be obvious that through a novel fabrication of the fins inthe heat transfer device, a coil is arranged so that two separate airstreams may flow across the face thereof without providing a separatewall or barrier member. This arrangement is accomplished withoutnecessity of employing expensive tooling. In addition to the advantagesdescribed above, it Will be observed that the protuberances 17 and 18also furnish to space the fins along the surface of .the tube.

The heat transfer device may also be formed of a section of continuoustubing if desired. The fins in this case would be provided with anadditional opening to accommodate the return bend portion upon assembly.

While we have described a preferred embodiment of the invention it willbe understood that the invention is not limited thereto since it may beotherwise embodied within the scope of the following claim.

We claim:

In an air conditioning unit including a housing having opposed sidewalls, an end wall and a cover forming a chamber having an open end; afan mounted within said chamber; means dividing the chamber into a faninlet section and a fan discharge section, said means including a coilengaging edge; a 'heat transfer coil mounted in the open end of saidhousing; a first group of extended surface elements angularly arrangedwith respect to the coil, having a portion, extending transversely ofthe element, upset from the plane thereof at a predetermined distancefrom one edge thereof, and a second group of extended surface elementsangularly arranged with respect to the coil, having a portion extendingtransversely of the element upset from the plane thereof at apredetermined distance from the edge corresponding to the edge used tomeasure .the distance in the first group, the distance measured in thesecond group being different than the distance measured in the firstgroup, the extended surface elements of each group being alternated withand parallel to the other group so that the upset portion of eachengages the confronting surface on the adjoining element to space theelements to form a continuous barrier; said coil engaging the chamberdividing means so that air induced through a portion of the coil intothe inlet portion of the chamber by the fan may be discharged throughthe coil from the discharge portion of the chamber without intermixingof the air stream within the coil.

References Cited in the file of this patent UNITED STATES PATENTS1,711,702 Spreen May 7, 1929 2,224,221 Galson Dec. 10, 1940 2,331,691Hubbard Oct. 12, 1943 2,359,051 Roper Sept. 26, 1944

